Mission accomplished.
Thanks to this Pin Out Diagram ...
The Ebay seller had my trigger wire tagged with + plus so all this time i've been trying to get a + current going through it ..... until today, i've had enough so i stripped everything down again .... started from scratch.
Anyway, there are so many wiring diagrams going around, don't follow any of them.
Best is to understand what sort of Relay do you have and most importantly, the TV needs a Ground/Earth signal for it to switch over, over-ride everything, even when the TV screen is OFF.
You won't need a good +12, you don't need direct power source from the battery if you're using the standard TV.
Simple! In the case if a 3 pin Relay is use ....
*Reverse light positive (+) to Relay
*Reverse light (-) to Relay
*(If you use 4pins relay, the extra pin will also need to be connect to a neg)
*Relay to Trigger wire
So when you engage reverse, reverse light + will activate Relay, Relay Jump/Bridge Reverse light Neg to Trigger wire, TV screen change to receive Video input from Reverse Cam.
Reverse Cam can be wire to any good 12+ sources on the vehicle, pending on where you're mounting the cam.